What are Antioxidants?
Compounds that act as antioxidants protect the body's cells from oxidative damage by supplying electrons to free radicals. Free radicals are substances naturally generated by the body during the conversion of food into energy, but also after physical activity or exposure to cigarette smoke, pollution and the sun. Oxidative stress, caused by a chronic excessive amount of free radicals in the body, can damage cells and lead to chronic diseases, such as cancer, heart disease, cognitive decline, etc.
Antioxidants and Health
Antioxidants are substances naturally present in certain foods, but they are also found in the form ofsupplements. To date, studies do not confirm that antioxidant supplementation provides substantial protection against chronic diseases (eg heart disease, cancer, etc.). Indeed, many studies on antioxidant supplements show no health benefits and high doses of antioxidant supplements could even be harmful in some cases.
On the other hand, several evidences suggest that the consumption offruits, vegetables and whole grains, all rich in natural antioxidants, provide protection against several age-related diseases. For example, prospective epidemiological studies show that higher consumption of fruits, vegetables and legumes is associated with a lower risk of chronic diseases related to oxidative stress, such as cardiovascular disease and cancer.
This difference between antioxidant supplements and natural antioxidants could be because antioxidants tend to be more effective when combined with other components found in foods. However, it is unclear whether this protective effect is due to the antioxidants themselves, other substances in food, or a combination of several factors.
What are the best food sources of antioxidants?
The most common antioxidant components include vitamins C and E, carotenoid pigments (eg beta-carotene, lycopene), and the mineral selenium. Added to this list are other related carotenoids, as well as manganese, glutathione, coenzyme Q10, lipoic acid, flavonoids, phenols, polyphenols, phytoestrogens and many more. They are mainly found in foods of plant origin, especially in fruits and vegetables, but also in whole grains, nuts, seeds and legumes.
Here is a list of some of the best food sources of antioxidants:
Vitamin C: Broccoli, spinach, Brussels sprouts, cantaloupe, cauliflower, collard greens, lemon, kiwi, strawberry, raspberry, mango, blueberry, papaya, guava, grapefruit, sweet potato, tomato and red pepper.
Vitamin E: Almond, avocado, Swiss chard, peanut, fish (eg mackerel, salmon, tuna), wheat germ, spinach and sunflower seed.
Phenolic compounds:
- Quercetin (e.g. apples, red wine, onions)
- Catechins or flavonoids (e.g.:tea,cocoa, berries, such as blueberries, strawberries, raspberries, cranberries, etc.)
- Resveratrol (ex.: red and white wine, grapes, berries, peanuts)
- Coumaric acid (ex.:spices, berries)
- Anthocyanins (ex.:blueberries, strawberries)
Carotenoids (e.g. beta-carotene, lycopene):Broccoli, carrot, tomato, tangerine, papaya, sweet potato, abricot, asparagus, beet,kale, mango, orange, pfish, pumpkin, spinach, cantaloupe and melon d'water.
Curcuminoids: turmeric
Selenium: Brazil nuts, fish, seafood, poultry, eggs, beef, and legumes.
References
- https://www.hsph.harvard.edu/nutritionsource/antioxidants/
- https://www.nccih.nih.gov/health/antioxidants-in-depth
- https://www.unlockfood.ca/en/Articles/Vitamins-and-Minerals/What-you-need-to-know-about-antioxidants.aspx
- https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/multimedia/antioxidants/sls-20076428
- Whitney, Eleanor N., et al.“The Antioxidant Nutrients. UnderstandingNutrition, Nelson Education, Toronto, 2013, p. 380–406.
Article written by:
Marie-Noël Marsan, Nutritionist